Sheet separating machines



Nov. 12,1957 WTEBB 2,812,942

' SHEET SEPARATING MACHINES Filed April 15, 1954 United States Patent SHEET SEPARATING MACHINES George William Tebbs, Walthamstow, London, England, assignor to Headley Townsend Backhouse, Nassau, Bahamas, British West Indies Application April 13, 1954, Serial No. 422,951

Claims priority, application Great Britain April 14, 1953 3 Claims. (Cl. 271-56) The invention relates to machines for separating sheets of paper, card or the like one by one from the top of a pile and is concerned with machines of this kind in which, as an initial step in the separation of each sheet an edge portion of the sheet is elevated from the pile. Example of machines of this kind are described in patent specification No. 2,108,702 and in the specification accompanying my application Serial No. 348,313, filed April 13, 1953, now Patent No. 2,761,679, issued September 4, 1956. Usually machines of this kind are associated with means for removing the separated sheets from the pile. Such removing means are also described in the above-mentioned specifications.

Machines of the above kind are commonly employed to supply individual sheets to printing presses, creasing machines and other machines operating on individual sheets.

It is important that any failure in the operation of such a separating machine to make a separated sheet available at the proper time shall be immediately detected and the effective operation of the machine stopped or a warning given. It is an object of the present invention to provide improved means which operate at an early stage in the separation of the sheets, to detect failure to separate a sheet at the correct time.

According to the invention a sheet separating machine of the above kind is provided with means for detecting failure to elevate the edge portion of a sheet at the proper time.

'In one construction according to the invention the detecting means comprise a feeler and there are operating means for the feeler which pass the feeler, or allow it to pass, through a position occupied by a raised portion of a sheet at the appropriate time to engage a properly elevated sheet, the operating means permitting movement of the feeler to be arrested by a raised portion of a sheet should it engage such a portion in its passage and there are sensing means operable to determine whether the feeler has been arrested as aforesaid and if it has not to stop the machine, or a part thereof and/or to operate a warning device. Preferably the feeler is arranged to move downwardly under the action of gravity or spring means through the position aforesaid and the operating means control the descent and permit the descent to be arrested by a sheet. The operating means may return the feeler ready for operation at the time appropriate to engage the next sheet to be elevated. When the invention is applied to a machine which completes the separation of the sheet by an upward movement, the operating means may be arranged to lift the feeler out of the upward path of the sheet.

The sensing means may, for example, comprise a latch which moves with the operating means and is deflected by the feeler should the feeler not be arrested by a sheet and pass through the position aforesaid, into a path in which it engages and operates a trip member.

As an example of how the invention may be carried Y 1 in the drive to the machine.

into effect, one specific construction of the detecting means, applied to the machine forming the subject of my said patent will now be described with reference to the accompanying drawings in which:

Figure 1 is a side view, to some extent diagrammatic, shgwing the detecting means at one side of the machine an Figure 2 is a plan view of part of the mechanism shown in Figure 1.

-In the following description reference numerals below 300 refer to corresponding parts shown in the drawings in this specification and in the drawings in my said patent.

The machine to which the invention is applied embodies, in the manner described and illustrated in my said patent, suction grippers which are lowered on to the uppermost sheet of a pile 20 adjacent the front corners thereof and are then moved upwardly and outwardly to elevate the front edge portion of the uppermost sheet and to tauten that portion, the front of the sheet then being as shown at 185. The raised and tautened front portion of the sheet is then transferred to mechanical grippers 151 carried on upwardly moving chains. There are two sets of suction and mechanical grippers adjacent the front corners of the pile respectively. The suction grippers are carried on a sub-frame which descends as the pile is consumed .and which includes cross-bars 37, 3S and a driving shaft 66. The suction grippers with their mechanical operating mechanism are carried on separator units mounted on the bars 37, 38 outside the gripper chains.

In accordance with the present invention there are provided on the sub-frame a pair of devices for detecting if the suction grippers should fail to elevate the edge portion of a sheet at the proper time. The devices are located between the two separator units and the adjacent gripper chains.

Each device comprises a bracket 300 supported on the bars 37, 33. Supported in hearings in the brackets 300 is a trip shaft 302 which, when rotated, drives a vertical shaft at the side of the machine to disconnect a clutch Freely pivoted on the shaft 302 there is, in each device, a feeler finger 303. The free end of the finger extends over the top of the pile 20. The finger is in the form of a blade which is secured at its root end to a bracket 304 pivoted on the shaft 302 and lightly urged to rotate in the clockwise direction by a spring 306. Also freely pivoted on the shaft 3&2 there is a lever 308 which carries at its lower end a roller 309 acting as a follower for a cam 310 on the shaft 66. The roller is held in engagement with the cam by a spring 311. The lever 308 has an abutment face 312 which co-operates with the underface of the bracket 304 to lift the feeler when the lever is rocked by the cam. Pivoted on the lever there is a latch 314 having a tail 315 which engages the underside of the feeler blade. Dependent from the shaft 302 and keyed thereto is an arm 316 constructed to make latching engagement with the latch 314 when the latter is raised. An adjustable stop 313 in the path of an arm 319 integral with the arm 316 .serves to limit clockwise rotation of the shaft 302 beyond the position shown.

The cam 310 is slidable along the shaft 66 and the lever 303, the bracket 304 and the arms 316, 3-19 are slidable along the shaft 302. The bracket 300 has fork arms 320, 321 which constrain the parts just mentioned to slide along the shafts 66 and 302 as the bracket 300 is adjusted along the bars 37, 38.

In the operation of the device, the cam 310 as it rotates first rocks the lever 308 to engage the face 312 with the bracket 304 and to lift the feeler finger 303 to the position shown at 303a. in this position the end of the finger is clear of the path of a sheet being removed upwardly from the pile by the mechanical chain grippers. Continued rotation of the cam permits downward movement of the lever 308 and the feeler to be lowered by gravity and the spring 306. This movement coincides with the transfer of a sheetif properly separated and elevated by the suction gripper-sto the grippers 151 and the lowering of the feeler is arrested by engagement of the feeler with the sheet, as shown in full lines in Figure 2. Further rotation of the cam permits continued downward movement of the lever 308. During this movement the tail 315 of the latch is held in engagement with the underside of the feeler-by the weight of the latch and the latch is held away from the arm 316. Consequently when the arm 308 is next moved upwardly by the cam it does so without engagement between the latch and the arm 316 and operation of the machine continues. If a sheet 185 has not been elevated at the proper time, the downward movement of the feeler 303 is not arrested and the feeler continues to move downwardly until it reaches the position 3031:. When in this position the feeler depresses the tail 315 and so rocks the latch 314 upwardly to the position shown in dash lines. The latch is now positioned to engage the arm 316 and when the arm 308 is next moved upwardly by the cam, the arm 316 and shaft 302 are rotated which disengages the main driving clutch and stops the machine.

It is a feature of the above construction that if the 1. A sheet separating and forwarding machine com prising means for lifting an edge portion of each uppermost sheet in turn of a pile of sheets and means for gripping and forwarding the sheet from the pile after lifting effective to cause the feeler to pass through a position which will be occupied by a raised portion of a sheet at the appropriate time to engage a properly elevated sheet before the forwarding of the sheet has begun, the operating means permitting movement of the feeler to be arrested be a raised portion of a sheet should it engage such a portion in its passage, in combination with sensing means operable to determine whether the feeler has been arrested as aforesaid and if the feeler has not been so arrested to stop the machine from separating further sheets.

2. A machine as claimed in claim 1 in which the forwarding means move upwardly from the pile with the sheet and the operating means lift the feeler out of the upward path of the sheet.

3. A sheet separating and forwarding machine comprising means for lifting an edge portion of each uppermost sheet in turn of a pile of sheets and means for gripping and forwarding the sheet from the pile after lifting as aforesaid characterized by a feeler, and operating means efiective to cause the feeler to pass through a position which will be occupied by a raised portion of a sheet at the appropriate time to engage a properly elevated sheet before the forwarding of the sheet has begun, the operating means permitting movement of the feeler to be arrested by a raised portion of a sheet should it engage such a portion in its passage, in combination with sensing means operable to determine whether the feeler has been arrested as aforesaid and if the feeler has not been so arrested to stop the machine from separating further sheets, which sensing means comprise a trip member and a latch, which latch moves with the operating means and is deflected by the feeler should the feeler not be engaged by a sheet and pass through the position aforesaid, into a path in which it engages and operates the trip member.

References Cited in the file of this patent UNITED STATES PATENTS 1,823,182 Wright Sept. 15, 1931 2,643,113 Williams June 23, 1953 FOREIGN PATENTS 293,384 Great Britain Feb. 7, 1929 

